I love this manga but trying to make someone jealous for attention or your own peace of mind is a real cunt move. Doing that shit is a one way ticket to a broken relationship.
@ZdrytchX - At first I thought there was a floating hand somewhere in the scene, then I thought maybe someone had taken a screen shot of the page with their mouse hovering over it, but now I think they just meant that the Mano's hand looks like the mouse hover hand icon. I guess it kinda looks like the icon... or they're just trolling us.
actually after looking at google images @oftentell it's actually the page before that page (page 11, digital page 12)
I guess you do it when you don't want to touch the other person out of respect (e.g. they hate being touched in general) or if you perceive them to be too gross to touch